Additional information:

Catfish

Ictalurus punctatus

What do they look like?

Channel catfish have smooth scales that are speckled, with a darker back to a light whitish belly. Their colors can vary from blue, to black, or olive. Generally in muddy water they are olive to yellowish white and in clear water they are blacker in color. The difference between channel catfish and other U. S. catfishes is the deeply forked caudal fin with the top of the fin larger than the bottom portion. There are two barbels on the upper jaw and four on the lower jaw. They have 24 to 29 rays in the anal fin. The upper jaw protrudes in front of the lower jaw. The dorsal and pectoral fins have hard spines whereas the other rays are soft like the anal and caudal fins. Males generally have larger heads than females and males are darker in body color than females. There is little difference between young and old fish other than size, but at very early ages channel catfish are transparent. (Wang, 1996)

Where do they live?

Channel catfish are native to the Neartic range, from lower Canada and throughout the midwest of the United States. Channel catfish have been introduced in the Palearctic in Cyprus, the Czech Republic, Romania, Slovakia, and Spain as well as Malaysia. (Elvira, 2001)

What kind of habitat do they need?

Channel catfish can live in both fresh and salt water and brackish water yet they are generally found in freshwater environments. Channel catfish are found in many bodies of water such as lakes, reservoirs and ponds and also in areas of moving water such as streams, creeks and rivers. The depth at which they are found varies but during most of the day they are found in deep holes, overhangs, other various locations that provide shelter or are at the bottom of a body of water. The surfaces at the bottoms of these bodies range from rocky, sandy and gravelly but channel catfish prefer muddy surface bottoms and clear water.

How do they grow?

After fertilization males protect the eggs and make sure they have enough oxygen. The eggs are sticky, so that they can be placed on objects, and their size ranges from 2.4 to 3.0 mm in diameter. The temperature of the water determines how long before the eggs are hatched. If the water is 24 to 26 °C hatching takes 7 to 10 days but if the water is 24 °C it takes 6 days. Ideal hatching time and temperature is 4-6 days at 25-27 °C.

The yolk sac is still present in the larval stage, and it is still large in comparison to the larvae in this stage. The larvae do not have teeth or pigment. They remain close to the nest at first but then move into shallow waters.

The next stage is the juvenile; these individuals are found in shallow waters and generally only have up to 10 rays on the pectoral fins. Juveniles stay together for several days or weeks and feed on small invertebrates. Between the age of two and three years they are able to reproduce. (Chapman, 2000; Wang, 1996)

How do they reproduce?

Channel catfish find a single mate during each season. Males court females to convince them to mate with them. The male and female mate in the summer but the relationship is established earlier in the year. Males and females mate by swimming together and releasing the eggs and sperm at the same time into a nest built by the female or both the male and female. After mating has occurred the male chases away the female and then guards the eggs until they hatch.

Channel catfish spawn in the summer. After hatching the juveniles take from two days to two weeks until they are independent. Channel catfish make nests in hidden places, for example, in enclosed cans, under overhangs or in deep holes that provide extra protection from predators.

Channel catfish parents invest a lot into their offspring. After spawning the male chases the female away from the nest, but she does not leave completely. She will protect her eggs from a distance. The male and female will attack predators and chase them away with an open mouth but will not eat them. The male also provides the juveniles with a source of food by burrowing, a process where the fish swim down into the mud on the bottom of the body of water and thrash from side to side stirring up food particles for the offspring to eat. The female also provides food for the juveniles by positioning her body about a meter above the nest and then releasing eggs for the juveniles to eat. Together the male and female provide protection and food for their young.

Parental Investment

pre-fertilization

provisioning

pre-hatching/birth

provisioning

male

female

protecting

male

female

pre-weaning/fledging

provisioning

male

female

protecting

male

female

How long do they live?

The life expectancy of a channel catfish is around 14 years old but they can exceed this number. In captivity the channel catfish is generally harvested after 2 years.

How do they behave?

Ictalurus punctatus are solitary except during mating courtship and protection of young. They are active during the night, moving around and finding food after dusk. During the day they will be most likely found in deep water with little activity. There is no clear cut home range for channel catfish. Like many river fish, channel catfish will migrate up and down stream.

How do they communicate with each other?

Taste buds are found on the interior of the mouth and over the body of the fish. Channel catfish can detect prey by "smelling" them through the water with their taste buds. Another characteristic of channel catfish is the ability to produce sounds, they are able to use an organ attached to their swimbladder to amplify sound vibrations, which may be a way of communicating with other catfish.

What do they eat?

Ictalurus punctatus can be thought of as one large mouth because there are taste buds located all over their body. The olfactory system is used mostly in consumption of food. Adult channel catfish, over 45 cm, consume fishes such as yellow perch and sunfish. The diet of adults consists of snails, algae, snakes, frogs, insects, aquatic plants, and even birds occasionally. Younger channel catfish are more consistently omnivorous, eating a large variety of plants and animals.

What eats them and how do they avoid being eaten?

The spines on the dorsal and pectoral fins are great anti-predator devices. A predator trying to eat a channel catfish could get impaled by a spine. Only large fish are capable of eating a channel catfish. The darker color of the channel catfish helps camouflage it in the bottom of a clear river, but in muddy water visibility is minimal and this would have less of an anti-predator adaptation. Juvenile catfish have many predators, including many birds, other carnivorous fishes and some insects. Also channel catfish eggs are an easy source of food for many animals but the protection from the parents enables the success of the future offspring.

What roles do they have in the ecosystem?

Channel catfish mainly interact with other animals in their ecosystem as predators or as prey. Some freshwater mussel species use channel catfish as a host for their larvae, the larvae travel in the gills of the catfish and fall out onto the bottoms of rivers and lakes, where they transform to adults.

Do they cause problems?

There are no known negative impacts of channel catfish on humans.

How do they interact with us?

Farm raising of channel catfish for food is a multimillion dollar business (Burden, 2004). (Burden, 2004)

Are they endangered?

The IUCN Red List, CITES appendices, and the US Endangered Species Act list the status of Ictalurus punctatus as not significant or not present, meaning there is no threat of this species going extinct.

Some more information...

The original scientific name was Ictalurus punctatus but it has been changed to Ictalurus punctatus. The original description was made in 1818 by Samuel Rafinesque. The text of the document is quoted next, “Mud-catfish…Sp 8. Ictalurus punctatus, Raf. Body whitish with gilt shades and many brown unequal dots on the sides, 8 barbs, 4 underneath, 2 lateral long and black, dorsal fin 7 rays, 1 spiny pectoral fins 6 rays, 1 spiny, anal 27 rays, later line a little curved beneath at the base, tail forked unequal upper lobe longer (Rafinesque Esq., 1818). (Rafinesque Esq., 1818)

Contributors

David Schoonover (author), University of Michigan-Ann Arbor, William Fink (editor, instructor), University of Michigan-Ann Arbor.